The Nature Of The Nitrocellulose Solution

This paper shows the influences of the different types of solvents, mixed-solvent ratio, nitrogen content, temperature and solution concentration on the viscosity of nitrocellulose solution. The results of the research indicate that the type of effective solvent has minimal effect on the viscosity of nitrocellulose. The mixed-solvent ratio and nitrogen content have larger effect on the viscosity. This influence of viscosity can be explained by the change of the conformational structure and condensed state of nitrocellulose. The influence of the temperature on the viscosity of the nitrocellulose solution is relative to the concentration of the solution, i.e. the higher thetemperature, the greater effect on the viscosity. The index relation η_r = k₁e^-k₂T . Theconcentration has great effect on the viscosity of nitrocellulose solvent. In η_sp/C～C , with highconcentration the curve bends upward with the increase of C because of the chain condensing. With low concentration the curve also bends upward because of absorption. The turning concentration of the former is correspondent with the coil touching concentration C^*, while that of the latter, which is defined as C_a, is commensurate with the coil contracting concentration C_s. The C_a values of nitrocellulose solution at different temperature are estimated. Secondly, the conformational characteristics of nitrocellulose, which is semi-rigid macromolecule, in solution are assessed by the method of viscosity. The assessment is significant but its mathematical treatment is very complex. Finally, the process of condensing the winding of nitrocellulose molecule in solution is studied with the method of viscosity and volume rejecting chromatography. The result shows that the decrease of viscosity and increase of reserved volume in the freezing process of nitrocellulose solution are not caused by decomposition but by inner chain condensing of nitrocellulose molecule. Based on the increment of refractive index, the structure of condensing state of nitrocellulose molecule in solution is predicted theoretically and the number of solventing solvent molecules in each chain of nitrocellulose molecule in solution is about 13.